Because of an operation-related issue, only the schematic was submitted. Now ,let me supplement the requried functionality and the issues.
1. After VIN12V is input through the DC connector， VIN12V can be connected to GPIO0 ( or other GPIO) of the TPS25751D through a voltage divider. The TPS25751D uses its ADC function to detect the presence of the 12V input. After that, communication is initiated through the CC pin to negotiate with the Type C connectedf device. The negotiation result should have the TPS25751D acting as the Source, and the Type C connected device acting as the sink.
2. Based on the above, the CC communication also needs to negotiate the power supply voltage and current. The TPS25751D should use the negotiation result to control the I2C-based BUCKBOOST converter to output the corresponding voltage, and enable the internal PPHV path to deliver power to VBUS_IN. [ Qrestion 1: The EVM is currently using a batter charging IC (BQ25798). Is it possible to replace it with a standard one-way output I2C buck-boost converter?]
3. When VIN12V is not inserted into the DC connector,and only a Type-C device is connected, the TPS25751D should support the dead battery mode,where it draws power from the VBUS of the Type-C interface.In this mode, the CC interface must negotiate for the VBUS to supply 5V to the internal system,with a current capability of more than 1.5A.
4. Based on the above "3", the PPHV path switch should be turned off. At the same time, GPIO3 (or another GPIO) should be set to low level to turn on the PFET. (When the PFET is not enabled,the GPIO is in a high-impedance (Hi-Z) state.)
5. Based on points 3 and 4,if VIN12V is inserted into the DC connector at this point, the TPS25751D should quickly detect the 12V input and switch the Type-C device to sink mode, while the TPS25751D becomes the source. After that, the system should operate according to the logic in steps 1 and 2.
Question 2: Please review the above logic point by point to see if it can be implemented as intended. Also, please help to identify whether any of the used pins are inappropriate.
